The present invention relates to a controller and a control method for an internal combustion engine that control an internal combustion engine equipped with a forced-induction device.
An intercooler is arranged in an internal combustion engine equipped with a forced-induction device. The intercooler cools intake air after the intake air is compressed by the forced-induction device so that the temperature of the intake air is increased. The intake-air cooling system, in which the intercooler is arranged, includes a radiator that releases heat from coolant and a pump that circulates the coolant.
If a foreign object such as a piece of cardboard or a plastic bag adheres to the radiator, sufficient heat release is hampered. This raises the temperature of the coolant that flows in the intake-air cooling system. If maintained in this state, the coolant may boil.
To prevent such overheating, Japanese Laid-Open Patent Publication No. 2016-79935 discloses reduction of the output of an internal combustion engine to prevent overheating of a forced-induction device. Also, Japanese Laid-Open Patent Publication No. 2009-103055 discloses lowering of forced-induction pressure to prevent overheating of an internal combustion engine.
If heat release by the radiator becomes insufficient and the temperature of the coolant becomes excessively high, forced induction may be limited to lower the forced-induction pressure.
However, since such limitation of the forced induction decreases the output of the internal combustion engine, the limitation of the forced induction for preventing overheating may significantly decrease the output of the engine.